Portable electronic device with plural memory areas

Abstract

A portable electronic device in which storage data supplied from an external device is stored in a deletable EEPROM or in a non-deletable EPROM in accordance with specified data added to the storage data and an indication of whether or not the storage data is deletable. When a plurality of areas in the EEPROM are to be accessed, data access is performed as if a single area were accessed. The number of bytes or bits as a processing unit is determined for each of the plurality of areas, and when data is written therein, attribute data is added for each processing unit. Specified data is stored together with data for discriminating the specified data, written upon use by a user, into alterable data, non-alterable data, deletable data, and non-deletable data. The alterable or deletable specified data can be altered or deleted when an alteration or deletion instruction is input and a coincidence is found between specified personal identification numbers.

What is claimed is: 
     
       1. A portable electronic device detachably connected to a host system, comprising: first memory means, divided into a plurality of areas, for storing write data in each area;   second memory means for storing, in accordance with the divided areas, a unit data length defining the length of data to be written in the respective divided areas of said first memory means;   means for receiving write data supplied from said host system;   means for dividing the received write data in accordance with the unit data length corresponding to the divided areas in which the received write data are to be stored;   means for storing the divided data in said first memory means; and   means for repetitively operating said dividing means and storing means until all of the divided received write data are stored in said first memory means.   
     
     
       2. The portable electronic device according to claim 1, wherein the unit data length stored in said second memory means is non-deletable. 
     
     
       3. The portable electronic device according to claim 1, wherein said second memory means further stores data which indicates whether the write data in said first memory means is deletable. 
     
     
       4. A portable electronic device detachably connected to a host system, comprising: first memory means, divided into a plurality of areas, for storing transaction data in each area;   second memory means for storing data indicating whether the transaction data is deletable;   means for receiving a command supplied from said host system;   means for discriminating whether the received command is a delete command;   means for deleting the transaction data stored in said first memory means in response to a delete command; and   means for inhibiting said deleting means from deleting the transaction data if the data stored in said second memory means indicates that said transaction data is non-deletable.   
     
     
       5. The portable electronic device according to claim 4, wherein the data stored in said second memory means indicating whether the transaction data is deletable is non-deletable. 
     
     
       6. A portable electronic device detachably connected to a host system, comprising: first memory means, divided into a plurality of areas, for storing transaction data in each area;   second memory means, divided into a plurality of areas which are each assigned identification data, for storing address data for addressing the plurality of divided areas in said first memory means;   means for receiving a command code and the identification data from said host system; and   means for accessing said second memory means, in response to the command code, to obtain the address data corresponding to the received identification data, and for accessing said first memory means so as to obtain the transaction data in accordance with the obtained address data.